shadow/libmisc/limits.c

490 lines
12 KiB
C
Raw Normal View History

/*
* Copyright (c) 1989 - 1994, Julianne Frances Haugh
* Copyright (c) 1996 - 1999, Marek Michałkiewicz
* Copyright (c) 2003 - 2006, Tomasz Kłoczko
* Copyright (c) 2007 - 2008, Nicolas François
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the copyright holders or contributors may not be used to
* endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Separated from setup.c. --marekm
* Resource limits thanks to Cristian Gafton.
*/
#include <config.h>
#ifndef USE_PAM
#ident "$Id$"
#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include "prototypes.h"
#include "defines.h"
#include <pwd.h>
#include "getdef.h"
#ifdef HAVE_SYS_RESOURCE_H
#include <sys/resource.h>
#define LIMITS
#endif
#ifdef LIMITS
#ifndef LIMITS_FILE
#define LIMITS_FILE "/etc/limits"
#endif
#define LOGIN_ERROR_RLIMIT 1
#define LOGIN_ERROR_LOGIN 2
/* Set a limit on a resource */
/*
* rlimit - RLIMIT_XXXX
* value - string value to be read
* multiplier - value*multiplier is the actual limit
*/
static int
setrlimit_value (unsigned int rlimit, const char *value,
unsigned int multiplier)
{
struct rlimit rlim;
long limit;
char **endptr = (char **) &value;
const char *value_orig = value;
limit = strtol (value, endptr, 10);
if ((0 == limit) && (value_orig == *endptr)) { /* no chars read */
return 0;
}
limit *= multiplier;
rlim.rlim_cur = limit;
rlim.rlim_max = limit;
if (setrlimit (rlimit, &rlim) != 0) {
return LOGIN_ERROR_RLIMIT;
}
return 0;
}
static int set_prio (const char *value)
{
int prio;
char **endptr = (char **) &value;
prio = strtol (value, endptr, 10);
if ((0 == prio) && (value == *endptr)) {
return 0;
}
if (setpriority (PRIO_PROCESS, 0, prio) != 0) {
return LOGIN_ERROR_RLIMIT;
}
return 0;
}
static int set_umask (const char *value)
{
mode_t mask;
char **endptr = (char **) &value;
mask = strtol (value, endptr, 8) & 0777;
if ((0 == mask) && (value == *endptr)) {
return 0;
}
(void) umask (mask);
return 0;
}
/* Counts the number of user logins and check against the limit */
static int check_logins (const char *name, const char *maxlogins)
{
#if HAVE_UTMPX_H
struct utmpx *ut;
#else
struct utmp *ut;
#endif
unsigned int limit, count;
char **endptr = (char **) &maxlogins;
const char *ml_orig = maxlogins;
limit = strtol (maxlogins, endptr, 10);
if ((0 == limit) && (ml_orig == *endptr)) { /* no chars read */
return 0;
}
if (0 == limit) { /* maximum 0 logins ? */
SYSLOG ((LOG_WARN, "No logins allowed for `%s'\n", name));
return LOGIN_ERROR_LOGIN;
}
count = 0;
#if HAVE_UTMPX_H
setutxent ();
while ((ut = getutxent ())) {
#else
setutent ();
while ((ut = getutent ())) {
#endif
if (USER_PROCESS != ut->ut_type) {
continue;
}
if ('\0' == ut->ut_user[0]) {
continue;
}
if (strncmp (name, ut->ut_user, sizeof (ut->ut_user)) != 0) {
continue;
}
count++;
if (count > limit) {
break;
}
}
#if HAVE_UTMPX_H
endutxent ();
#else
endutent ();
#endif
/*
* This is called after setutmp(), so the number of logins counted
* includes the user who is currently trying to log in.
*/
if (count > limit) {
SYSLOG ((LOG_WARN, "Too many logins (max %d) for %s\n",
limit, name));
return LOGIN_ERROR_LOGIN;
}
return 0;
}
/* Function setup_user_limits - checks/set limits for the curent login
* Original idea from Joel Katz's lshell. Ported to shadow-login
* by Cristian Gafton - gafton@sorosis.ro
*
* We are passed a string of the form ('BASH' constants for ulimit)
* [Aa][Cc][Dd][Ff][Mm][Nn][Rr][Ss][Tt][Uu][Ll][Pp][Ii][Oo]
* (eg. 'C2F256D2048N5' or 'C2 F256 D2048 N5')
* where:
* [Aa]: a = RLIMIT_AS max address space (KB)
* [Cc]: c = RLIMIT_CORE max core file size (KB)
* [Dd]: d = RLIMIT_DATA max data size (KB)
* [Ff]: f = RLIMIT_FSIZE max file size (KB)
* [Mm]: m = RLIMIT_MEMLOCK max locked-in-memory address space (KB)
* [Nn]: n = RLIMIT_NOFILE max number of open files
* [Rr]: r = RLIMIT_RSS max resident set size (KB)
* [Ss]: s = RLIMIT_STACK max stack size (KB)
* [Tt]: t = RLIMIT_CPU max CPU time (MIN)
* [Uu]: u = RLIMIT_NPROC max number of processes
* [Kk]: k = file creation masK (umask)
* [Ll]: l = max number of logins for this user
* [Pp]: p = process priority -20..20 (negative = high, positive = low)
* [Ii]: i = RLIMIT_NICE max nice value (0..39 translates to 20..-19)
* [Oo]: o = RLIMIT_RTPRIO max real time priority (linux/sched.h 0..MAX_RT_PRIO)
*
* Return value:
* 0 = okay, of course
* LOGIN_ERROR_RLIMIT = error setting some RLIMIT
* LOGIN_ERROR_LOGIN = error - too many logins for this user
*
* buf - the limits string
* name - the username
*/
static int do_user_limits (const char *buf, const char *name)
{
const char *pp;
int retval = 0;
bool reported = false;
pp = buf;
while ('\0' != *pp) {
switch (*pp++) {
#ifdef RLIMIT_AS
case 'a':
case 'A':
/* RLIMIT_AS - max address space (KB) */
retval |= setrlimit_value (RLIMIT_AS, pp, 1024);
break;
#endif
#ifdef RLIMIT_CPU
case 't':
case 'T':
/* RLIMIT_CPU - max CPU time (MIN) */
retval |= setrlimit_value (RLIMIT_CPU, pp, 60);
break;
#endif
#ifdef RLIMIT_DATA
case 'd':
case 'D':
/* RLIMIT_DATA - max data size (KB) */
retval |= setrlimit_value (RLIMIT_DATA, pp, 1024);
break;
#endif
#ifdef RLIMIT_FSIZE
case 'f':
case 'F':
/* RLIMIT_FSIZE - Maximum filesize (KB) */
retval |= setrlimit_value (RLIMIT_FSIZE, pp, 1024);
break;
#endif
#ifdef RLIMIT_NPROC
case 'u':
case 'U':
/* RLIMIT_NPROC - max number of processes */
retval |= setrlimit_value (RLIMIT_NPROC, pp, 1);
break;
#endif
#ifdef RLIMIT_CORE
case 'c':
case 'C':
/* RLIMIT_CORE - max core file size (KB) */
retval |= setrlimit_value (RLIMIT_CORE, pp, 1024);
break;
#endif
#ifdef RLIMIT_MEMLOCK
case 'm':
case 'M':
/* RLIMIT_MEMLOCK - max locked-in-memory address space (KB) */
retval |= setrlimit_value (RLIMIT_MEMLOCK, pp, 1024);
break;
#endif
#ifdef RLIMIT_NOFILE
case 'n':
case 'N':
/* RLIMIT_NOFILE - max number of open files */
retval |= setrlimit_value (RLIMIT_NOFILE, pp, 1);
break;
#endif
#ifdef RLIMIT_RSS
case 'r':
case 'R':
/* RLIMIT_RSS - max resident set size (KB) */
retval |= setrlimit_value (RLIMIT_RSS, pp, 1024);
break;
#endif
#ifdef RLIMIT_STACK
case 's':
case 'S':
/* RLIMIT_STACK - max stack size (KB) */
retval |= setrlimit_value (RLIMIT_STACK, pp, 1024);
break;
#endif
#ifdef RLIMIT_NICE
case 'i':
case 'I':
/* RLIMIT_NICE - max scheduling priority (0..39) */
retval |= setrlimit_value (RLIMIT_NICE, pp, 1);
break;
#endif
#ifdef RLIMIT_RTPRIO
case 'o':
case 'O':
/* RLIMIT_RTPRIO - max real time priority (0..MAX_RT_PRIO) */
retval |= setrlimit_value (RLIMIT_RTPRIO, pp, 1);
break;
#endif
case 'k':
case 'K':
retval |= set_umask (pp);
break;
case 'l':
case 'L':
/* LIMIT the number of concurrent logins */
retval |= check_logins (name, pp);
break;
case 'p':
case 'P':
retval |= set_prio (pp);
break;
default:
/* Only report invalid strings once */
if (!reported) {
SYSLOG ((LOG_WARN,
"Invalid limit string: '%s'",
pp-1));
reported = true;
retval |= LOGIN_ERROR_RLIMIT;
}
}
}
return retval;
}
static int setup_user_limits (const char *uname)
{
/* TODO: allow and use @group syntax --cristiang */
FILE *fil;
char buf[1024];
char name[1024];
char limits[1024];
char deflimits[1024];
char tempbuf[1024];
/* init things */
memzero (buf, sizeof (buf));
memzero (name, sizeof (name));
memzero (limits, sizeof (limits));
memzero (deflimits, sizeof (deflimits));
memzero (tempbuf, sizeof (tempbuf));
/* start the checks */
fil = fopen (LIMITS_FILE, "r");
if (fil == NULL) {
return 0;
}
/* The limits file have the following format:
* - '#' (comment) chars only as first chars on a line;
* - username must start on first column
* A better (smarter) checking should be done --cristiang */
while (fgets (buf, 1024, fil) != NULL) {
if (('#' == buf[0]) || ('\n' == buf[0])) {
continue;
}
memzero (tempbuf, sizeof (tempbuf));
/* a valid line should have a username, then spaces,
* then limits
* we allow the format:
* username L2 D2048 R4096
* where spaces={' ',\t}. Also, we reject invalid limits.
* Imposing a limit should be done with care, so a wrong
* entry means no care anyway :-). A '-' as a limits
* strings means no limits --cristiang */
if (sscanf (buf, "%s%[ACDFMNRSTULPIOacdfmnrstulpio0-9 \t-]",
name, tempbuf) == 2) {
if (strcmp (name, uname) == 0) {
strcpy (limits, tempbuf);
break;
} else if (strcmp (name, "*") == 0) {
strcpy (deflimits, tempbuf);
}
}
}
(void) fclose (fil);
if (limits[0] == '\0') {
/* no user specific limits */
if (deflimits[0] == '\0') { /* no default limits */
return 0;
}
strcpy (limits, deflimits); /* use the default limits */
}
return do_user_limits (limits, uname);
}
#endif /* LIMITS */
static void setup_usergroups (const struct passwd *info)
{
const struct group *grp;
mode_t oldmask;
/*
* if not root, and UID == GID, and username is the same as primary
* group name, set umask group bits to be the same as owner bits
* (examples: 022 -> 002, 077 -> 007).
*/
if ((0 != info->pw_uid) && (info->pw_uid == info->pw_gid)) {
* lib/prototypes.h, configure.in, libmisc/Makefile.am, libmisc/xgetXXbyYY.c, libmisc/xgetpwnam.c, libmisc/xgetpwuid.c, libmisc/xgetgrnam.c, libmisc/xgetgrgid.c, libmisc/xgetspnam.c: Added functions xgetpwnam(), xgetpwuid(), xgetgrnam(), xgetgrgid(), and xgetspnam(). They allocate memory for the returned structure and are more robust to successive calls. They are implemented with the libc's getxxyyy_r() functions if available. * libmisc/limits.c, libmisc/entry.c, libmisc/chowntty.c, libmisc/addgrps.c, libmisc/myname.c, libmisc/rlogin.c, libmisc/pwdcheck.c, src/newgrp.c, src/login_nopam.c, src/userdel.c, src/lastlog.c, src/grpck.c, src/gpasswd.c, src/newusers.c, src/chpasswd.c, src/chfn.c, src/groupmems.c, src/usermod.c, src/expiry.c, src/groupdel.c, src/chgpasswd.c, src/su.c, src/useradd.c, src/groupmod.c, src/passwd.c, src/pwck.c, src/groupadd.c, src/chage.c, src/login.c, src/suauth.c, src/faillog.c, src/groups.c, src/chsh.c, src/id.c: Review all the usage of one of the getpwnam(), getpwuid(), getgrnam(), getgrgid(), and getspnam() functions. It was noticed on http://bugs.debian.org/341230 that chfn and chsh use a passwd structure after calling a pam function, which result in using information from the passwd structure requested by pam, not the original one. It is much easier to use the new xget... functions to avoid these issues. I've checked which call to the original get... functions could be left (reducing the scope of the structure if possible), and I've left comments to ease future reviews (e.g. /* local, no need for xgetpwnam */). Note: the getpwent/getgrent calls should probably be checked also. * src/groupdel.c, src/expiry.c: Fix typos in comments. * src/groupmod.c: Re-indent. * libmisc/Makefile.am, lib/groupmem.c, lib/groupio.c, lib/pwmem.c, lib/pwio.c, lib/shadowmem.c, lib/shadowio.c: Move the __<xx>_dup functions (used by the xget... functions) from the <xx>io.c files to the new <xx>mem.c files. This avoid linking some utils against the SELinux library.
2007-11-19 04:45:26 +05:30
/* local, no need for xgetgrgid */
grp = getgrgid (info->pw_gid);
if ( (NULL != grp)
&& (strcmp (info->pw_name, grp->gr_name) == 0)) {
oldmask = umask (0777);
(void) umask ((oldmask & ~070) | ((oldmask >> 3) & 070));
}
}
}
/*
* set the process nice, ulimit, and umask from the password file entry
*/
void setup_limits (const struct passwd *info)
{
char *cp;
int i;
long l;
if (getdef_bool ("USERGROUPS_ENAB")) {
setup_usergroups (info);
}
/*
* See if the GECOS field contains values for NICE, UMASK or ULIMIT.
* If this feature is enabled in /etc/login.defs, we make those
* values the defaults for this login session.
*/
if (getdef_bool ("QUOTAS_ENAB")) {
#ifdef LIMITS
if (info->pw_uid != 0) {
if (setup_user_limits (info->pw_name) &
LOGIN_ERROR_LOGIN) {
(void) fputs (_("Too many logins.\n"), stderr);
(void) sleep (2); /* XXX: Should be FAIL_DELAY */
exit (1);
}
}
#endif
for (cp = info->pw_gecos; cp != NULL; cp = strchr (cp, ',')) {
if (',' == *cp) {
cp++;
}
if (strncmp (cp, "pri=", 4) == 0) {
i = atoi (cp + 4);
if ((i >= -20) && (i <= 20)) {
errno = 0;
if ( (nice (i) == -1)
&& (0 != errno)) {
SYSLOG ((LOG_WARN,
"Can't set the nice value for user %s",
info->pw_name));
}
}
continue;
}
if (strncmp (cp, "ulimit=", 7) == 0) {
l = strtol (cp + 7, (char **) 0, 10);
if (set_filesize_limit (l) != 0) {
SYSLOG ((LOG_WARN,
"Can't set the ulimit for user %s",
info->pw_name));
}
continue;
}
if (strncmp (cp, "umask=", 6) == 0) {
i = strtol (cp + 6, (char **) 0, 8) & 0777;
(void) umask (i);
continue;
}
}
}
}
#else /* !USE_PAM */
extern int errno; /* warning: ANSI C forbids an empty source file */
#endif /* !USE_PAM */